ESTIMATION OF MIXED LINKAGE BETA-GLUCAN CONCENTRATION IN OAT AND BARLEY FROM VISCOSITY OF WHOLE GRAIN FLOUR SLURRY

The presence of beta-glucan from oat (Avena sativa L.) or barley (Hord eum vulgare L.) products in the human diet can lower serum cholesterol . The selection of new oat or barley cultivars with higher beta-glucan concentration in the grain is usually limited by the efficiency of th e analytical procedure required to measure this component. The utility of hour slurry viscosity as an indirect means of estimating flour bet a-glucan concentration was investigated. Water at 25 degrees C was add ed to enzyme-inactivated whole-grain oat flour to form a 23% dry matte r mixture, and stirred to form a uniform slurry. Viscosity, as measure d with a rotational spindle-type viscometer, increased hyperbolically with time. Viscosity measured 3 h after water addition was exponential ly dependent on hour content and was linearly correlated with beta-glu can concentration in the hour. The procedure was useful as a screening method for the estimation of beta-glucan concentration in preliminary breeding lines of oat and barley. The procedure is effective with enz yme-inactivated (steam-treated) whole or dehulled grain, but the prese nce of endo-beta-glucanases in hulls of oats and barley prevent the ap plication of this procedure with hours of raw whole oats and barleys.